But what should they be doing otherwise?

Anything.  My son will spend every waking moment on his computer if I let him.  I just put up his basketball hoop, go outside, get some fucking sun son!  Do your homework!  Help me with projects!

Do you ask him to do these things? Sounds like he definitely needs a hobby of some sort. 

If it helps, I basically the same. The only real exception was cadets which was a huge exception, admittedly.

Anyway, end result is computers pay the bills and I can't afford all of my offline hobbies!

I am too. I'm not the driving force behind this but I am the one who gets to hear about it non fucking stop.